On 01/21/2018 04:04 PM, Rob Jarratt wrote:
You might find that the filter capacitor goes up in smoke soon after you connect the PSU to the mains, even without powering it on.
Yes, Adrian Graham mentioned that (via FB), too. I seem to have extremely good luck with the RF filter caps, unlike other people, but I'm always prepared for the cloud of smoke :-)
Otherwise it is certainly wise to check the PSU visually for any obviously failed electrolytics. If you have one of the DEC load boards you could connect the PSU to that as a dummy load. I don't think there is much in the way of dependency on the CPU to run the PSU.
At this stage I've got no idea if it's a SMPSU or a linear (I've not popped the panel off)... I suppose if it's linear then it perhaps doesn't even need a load to do its thing. If it's a switcher then I expect it'll at least need something on +5V, and maybe +12V too (unless it has built-in load resistors to keep the regulation happy, as designs occasionally do).
I see on the output rating label that it lists connection points for different outputs, so maybe I just need to slap a couple of suitable resistors onto the +5V and +12V outputs so that they draw an amp or so, and see how it goes.
Once you have the machine up and running...
Lets not get ahead of ourselves ;-)
I am not sure if 4MB is enough to do that though.
Hmm, one of the things that I'm clueless about right now is how the bus evolved over the years - I've still got a pile of Q-bus boards which I saved from a recycler last year, and I know there's a 4MB board (made by Clearpoint, if I remember right) among them. But if that's designed for earlier PDP hardware then it's possibly no use whatsoever in a Vax world...
cheers Jules
